The work in this project will be concerned with: 1. Biochemical studies of polyoma virus-infected mouse kidney cells. 2. Characterization of the polyoma virus particles by immunochemical, chemical, and physicochemical techniques. BIBLIOGRAPHIC REFERENCES: L. Kahan, W.A. Fenton and W.T. Murakami, "Specificity and Distribution of Antigenic Determinants on the Polyoma virus Capsid and Nature of the Reaction of Immunoglobulin G Antibody with the Capsid Surface". J. Molecular Biology 95, 239-256 (1975).